1 //! This module implements import-resolution/macro expansion algorithm.
3 //! The result of this module is `CrateDefMap`: a data structure which contains:
5 //! * a tree of modules for the crate
6 //! * for each module, a set of items visible in the module (directly declared
9 //! Note that `CrateDefMap` contains fully macro expanded code.
11 //! Computing `CrateDefMap` can be partitioned into several logically
12 //! independent "phases". The phases are mutually recursive though, there's no
15 //! ## Collecting RawItems
17 //! This happens in the `raw` module, which parses a single source file into a
18 //! set of top-level items. Nested imports are desugared to flat imports in this
19 //! phase. Macro calls are represented as a triple of (Path, Option<Name>,
22 //! ## Collecting Modules
24 //! This happens in the `collector` module. In this phase, we recursively walk
25 //! tree of modules, collect raw items from submodules, populate module scopes
26 //! with defined items (so, we assign item ids in this phase) and record the set
27 //! of unresolved imports and macros.
29 //! While we walk tree of modules, we also record macro_rules definitions and
30 //! expand calls to macro_rules defined macros.
32 //! ## Resolving Imports
34 //! We maintain a list of currently unresolved imports. On every iteration, we
35 //! try to resolve some imports from this list. If the import is resolved, we
36 //! record it, by adding an item to current module scope and, if necessary, by
37 //! recursively populating glob imports.
39 //! ## Resolving Macros
41 //! macro_rules from the same crate use a global mutable namespace. We expand
42 //! them immediately, when we collect modules.
44 //! Macros from other crates (including proc-macros) can be used with
45 //! `foo::bar!` syntax. We handle them similarly to imports. There's a list of
46 //! unexpanded macros. On every iteration, we try to resolve each macro call
47 //! path and, upon success, we run macro expansion and "collect module" phase on
61 use base_db::{CrateId, Edition, FileId};
62 use hir_expand::{name::Name, InFile, MacroDefId};
65 use rustc_hash::FxHashMap;
71 item_scope::{BuiltinShadowMode, ItemScope},
72 nameres::{diagnostics::DefDiagnostic, path_resolution::ResolveMode},
75 AstId, BlockId, BlockLoc, LocalModuleId, ModuleDefId, ModuleId,
78 use self::proc_macro::ProcMacroDef;
80 /// Contains the results of (early) name resolution.
82 /// A `DefMap` stores the module tree and the definitions that are in scope in every module after
83 /// item-level macros have been expanded.
85 /// Every crate has a primary `DefMap` whose root is the crate's main file (`main.rs`/`lib.rs`),
86 /// computed by the `crate_def_map` query. Additionally, every block expression introduces the
87 /// opportunity to write arbitrary item and module hierarchies, and thus gets its own `DefMap` that
88 /// is computed by the `block_def_map` query.
89 #[derive(Debug, PartialEq, Eq)]
92 block: Option<BlockInfo>,
94 modules: Arena<ModuleData>,
96 /// The prelude module for this crate. This either comes from an import
97 /// marked with the `prelude_import` attribute, or (in the normal case) from
98 /// a dependency (`std` or `core`).
99 prelude: Option<ModuleId>,
100 extern_prelude: FxHashMap<Name, ModuleDefId>,
102 /// Side table with additional proc. macro info, for use by name resolution in downstream
105 /// (the primary purpose is to resolve derive helpers)
106 exported_proc_macros: FxHashMap<MacroDefId, ProcMacroDef>,
109 diagnostics: Vec<DefDiagnostic>,
112 /// For `DefMap`s computed for a block expression, this stores its location in the parent map.
113 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
115 /// The `BlockId` this `DefMap` was created from.
117 /// The containing module.
121 impl std::ops::Index<LocalModuleId> for DefMap {
122 type Output = ModuleData;
123 fn index(&self, id: LocalModuleId) -> &ModuleData {
128 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
129 pub enum ModuleOrigin {
133 /// Note that non-inline modules, by definition, live inside non-macro file.
136 declaration: AstId<ast::Module>,
140 definition: AstId<ast::Module>,
142 /// Pseudo-module introduced by a block scope (contains only inner items).
144 block: AstId<ast::BlockExpr>,
148 impl Default for ModuleOrigin {
149 fn default() -> Self {
150 ModuleOrigin::CrateRoot { definition: FileId(0) }
155 fn declaration(&self) -> Option<AstId<ast::Module>> {
157 ModuleOrigin::File { declaration: module, .. }
158 | ModuleOrigin::Inline { definition: module, .. } => Some(*module),
159 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::BlockExpr { .. } => None,
163 pub fn file_id(&self) -> Option<FileId> {
165 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
172 pub fn is_inline(&self) -> bool {
174 ModuleOrigin::Inline { .. } | ModuleOrigin::BlockExpr { .. } => true,
175 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::File { .. } => false,
179 /// Returns a node which defines this module.
180 /// That is, a file or a `mod foo {}` with items.
181 fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
183 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
184 let file_id = *definition;
185 let sf = db.parse(file_id).tree();
186 InFile::new(file_id.into(), ModuleSource::SourceFile(sf))
188 ModuleOrigin::Inline { definition } => InFile::new(
190 ModuleSource::Module(definition.to_node(db.upcast())),
192 ModuleOrigin::BlockExpr { block } => {
193 InFile::new(block.file_id, ModuleSource::BlockExpr(block.to_node(db.upcast())))
199 #[derive(Default, Debug, PartialEq, Eq)]
200 pub struct ModuleData {
201 pub parent: Option<LocalModuleId>,
202 pub children: FxHashMap<Name, LocalModuleId>,
203 pub scope: ItemScope,
205 /// Where does this module come from?
206 pub origin: ModuleOrigin,
210 pub(crate) fn crate_def_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<DefMap> {
211 let _p = profile::span("crate_def_map_query").detail(|| {
212 db.crate_graph()[krate].display_name.as_deref().unwrap_or_default().to_string()
214 let edition = db.crate_graph()[krate].edition;
215 let def_map = DefMap::empty(krate, edition);
216 let def_map = collector::collect_defs(db, def_map, None);
220 pub(crate) fn block_def_map_query(
221 db: &dyn DefDatabase,
223 ) -> Option<Arc<DefMap>> {
224 let block: BlockLoc = db.lookup_intern_block(block_id);
226 let item_tree = db.file_item_tree(block.ast_id.file_id);
227 if item_tree.inner_items_of_block(block.ast_id.value).is_empty() {
231 let block_info = BlockInfo { block: block_id, parent: block.module };
233 let parent_map = block.module.def_map(db);
234 let mut def_map = DefMap::empty(block.module.krate, parent_map.edition);
235 def_map.block = Some(block_info);
237 let def_map = collector::collect_defs(db, def_map, Some(block.ast_id));
238 Some(Arc::new(def_map))
241 fn empty(krate: CrateId, edition: Edition) -> DefMap {
242 let mut modules: Arena<ModuleData> = Arena::default();
243 let root = modules.alloc(ModuleData::default());
249 extern_prelude: FxHashMap::default(),
250 exported_proc_macros: FxHashMap::default(),
254 diagnostics: Vec::new(),
258 pub fn modules_for_file(&self, file_id: FileId) -> impl Iterator<Item = LocalModuleId> + '_ {
261 .filter(move |(_id, data)| data.origin.file_id() == Some(file_id))
262 .map(|(id, _data)| id)
265 pub fn modules(&self) -> impl Iterator<Item = (LocalModuleId, &ModuleData)> + '_ {
269 pub fn root(&self) -> LocalModuleId {
273 pub(crate) fn krate(&self) -> CrateId {
277 pub(crate) fn block_id(&self) -> Option<BlockId> {
278 self.block.as_ref().map(|block| block.block)
281 pub(crate) fn prelude(&self) -> Option<ModuleId> {
285 pub(crate) fn extern_prelude(&self) -> impl Iterator<Item = (&Name, &ModuleDefId)> + '_ {
286 self.extern_prelude.iter()
289 pub fn module_id(&self, local_id: LocalModuleId) -> ModuleId {
290 let block = self.block.as_ref().map(|b| b.block);
291 ModuleId { krate: self.krate, local_id, block }
294 pub(crate) fn crate_root(&self, db: &dyn DefDatabase) -> ModuleId {
295 self.with_ancestor_maps(db, self.root, &mut |def_map, _module| {
296 if def_map.block.is_none() {
297 Some(def_map.module_id(def_map.root))
302 .expect("DefMap chain without root")
305 pub(crate) fn resolve_path(
307 db: &dyn DefDatabase,
308 original_module: LocalModuleId,
310 shadow: BuiltinShadowMode,
311 ) -> (PerNs, Option<usize>) {
313 self.resolve_path_fp_with_macro(db, ResolveMode::Other, original_module, path, shadow);
314 (res.resolved_def, res.segment_index)
317 pub(crate) fn resolve_path_locally(
319 db: &dyn DefDatabase,
320 original_module: LocalModuleId,
322 shadow: BuiltinShadowMode,
323 ) -> (PerNs, Option<usize>) {
324 let res = self.resolve_path_fp_with_macro_single(
331 (res.resolved_def, res.segment_index)
334 /// Ascends the `DefMap` hierarchy and calls `f` with every `DefMap` and containing module.
336 /// If `f` returns `Some(val)`, iteration is stopped and `Some(val)` is returned. If `f` returns
337 /// `None`, iteration continues.
338 pub fn with_ancestor_maps<T>(
340 db: &dyn DefDatabase,
341 local_mod: LocalModuleId,
342 f: &mut dyn FnMut(&DefMap, LocalModuleId) -> Option<T>,
344 if let Some(it) = f(self, local_mod) {
347 let mut block = self.block;
348 while let Some(block_info) = block {
349 let parent = block_info.parent.def_map(db);
350 if let Some(it) = f(&parent, block_info.parent.local_id) {
353 block = parent.block;
359 /// If this `DefMap` is for a block expression, returns the module containing the block (which
360 /// might again be a block, or a module inside a block).
361 pub fn parent(&self) -> Option<ModuleId> {
362 Some(self.block?.parent)
365 /// Returns the module containing `local_mod`, either the parent `mod`, or the module containing
366 /// the block, if `self` corresponds to a block expression.
367 pub fn containing_module(&self, local_mod: LocalModuleId) -> Option<ModuleId> {
368 match &self[local_mod].parent {
369 Some(parent) => Some(self.module_id(*parent)),
370 None => self.block.as_ref().map(|block| block.parent),
374 // FIXME: this can use some more human-readable format (ideally, an IR
375 // even), as this should be a great debugging aid.
376 pub fn dump(&self, db: &dyn DefDatabase) -> String {
377 let mut buf = String::new();
379 let mut current_map = self;
380 while let Some(block) = ¤t_map.block {
381 go(&mut buf, current_map, "block scope", current_map.root);
383 arc = block.parent.def_map(db);
386 go(&mut buf, current_map, "crate", current_map.root);
389 fn go(buf: &mut String, map: &DefMap, path: &str, module: LocalModuleId) {
390 format_to!(buf, "{}\n", path);
392 map.modules[module].scope.dump(buf);
394 for (name, child) in map.modules[module].children.iter() {
395 let path = format!("{}::{}", path, name);
397 go(buf, map, &path, *child);
402 pub fn dump_block_scopes(&self, db: &dyn DefDatabase) -> String {
403 let mut buf = String::new();
405 let mut current_map = self;
406 while let Some(block) = ¤t_map.block {
407 format_to!(buf, "{:?} in {:?}\n", block.block, block.parent);
408 arc = block.parent.def_map(db);
412 format_to!(buf, "crate scope\n");
416 fn shrink_to_fit(&mut self) {
417 // Exhaustive match to require handling new fields.
420 exported_proc_macros,
431 extern_prelude.shrink_to_fit();
432 exported_proc_macros.shrink_to_fit();
433 diagnostics.shrink_to_fit();
434 modules.shrink_to_fit();
435 for (_, module) in modules.iter_mut() {
436 module.children.shrink_to_fit();
437 module.scope.shrink_to_fit();
441 /// Get a reference to the def map's diagnostics.
442 pub fn diagnostics(&self) -> &[DefDiagnostic] {
443 self.diagnostics.as_slice()
448 /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
449 pub fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
450 self.origin.definition_source(db)
453 /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
454 /// `None` for the crate root or block.
455 pub fn declaration_source(&self, db: &dyn DefDatabase) -> Option<InFile<ast::Module>> {
456 let decl = self.origin.declaration()?;
457 let value = decl.to_node(db.upcast());
458 Some(InFile { file_id: decl.file_id, value })
462 #[derive(Debug, Clone, PartialEq, Eq)]
463 pub enum ModuleSource {
464 SourceFile(ast::SourceFile),
466 BlockExpr(ast::BlockExpr),